Pure silver, also called fine silver, is relatively soft, very workable, and easily damaged so it's commonly combined with other metals to produce more durable jewelry. The most popular of these alloys is sterling silver, which consists of 92.5 percent silver and 7.5 percent copper.
80% pure silver and 20% other alloys. It makes for a more durable product. Sterling Silver is .925 ie 92.5% silver and 7.5% other alloy. 0.800 silver is the lowest percentage mix that can be called 'Silver'